1. Field of the Invention
The present invention relates generally to flush valves used in connection with plumbing fixtures, such as toilets, urinals and the like, and in particular, to a replacement for a diaphragm valve in such a plumbing fixture.
2. Description of Related Art
Valves are used throughout many fluid transfer systems and in various applications, such as in the transfer and control of water conduit systems, and in particular in connection with plumbing fixtures in both residential and commercial settings. For example, flush valves are typically used for control and operation of toilets, urinals and the like, such that when a user actuates a handle, water flows through the flush valve into a basin portion and out the drain.
Presently, a common type of flush valve is a diaphragm flush valve. For example, such a diaphragm flush valve is disclosed in U.S. Pat. No. 4,327,891 to Allen et al. The Allen patent discloses the use of a diaphragm in a flush valve, where the diaphragm is made of molded rubber and serves to effectuate the flow of water from a water inlet, through the valve and to a water outlet. Further, the Allen patent sets forth the various components and sub-components of the flush valve according to the prior art.
Such diaphragm flush valves have several drawbacks. For example, the relatively small seal area in the diaphragm can become clogged with debris, which causes the flush valve to remain open, resulting in constant water flow. In addition, since the flush valve is pressurized, a small bleed hole is used in order to allow enough volume to flow through the valve in order to flush the toilet or urinal. This small bleed hole is easily clogged, which can also result in the malfunction of the valve. Still further, the flushing cycle of the diaphragm flush valve takes approximately seven seconds to complete, depending upon the flow rates and water pressure entering the valve, due to the design of the diaphragm of the flush valve. Since an upper chamber fills slowly, the valve is slowly “shutting off”. Therefore, a significant amount of water is wasted through the trap and sewer line during the sealing process. The trip lever seal area can also be blocked with debris, which causes the valve to flow continuously. Yet another drawback is that conventional diaphragm flush valves only work at water pressures greater than 35 psi, which is due to the difference in the diaphragm surface area and the diameter of the bleed hole.
Pinch valves have found use in various valve applications other than a diaphragm-type valve. For example, U.S. Pat. No. 4,111,391 to Pilolla discloses a pinch valve including a distortable rubber-like valve member in a generally cylindrical form. As disclosed in the Pilolla patent, the valve member has uniformly spaced projections and grooves enabling it to collapse upon itself and form a complete closure between opposite ends. Heretofore, however, the use of such a pinch valve as a replacement valve in the application of flush valves for plumbing fixtures has not been effective due to the different sealing arrangement bound in pinch valves in comparison to diaphragm valves. Therefore, there remains a need for an effective valve for replacing a diaphragm flush valve in a plumbing fixture.